In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date:                (i) part of common general knowledge; or        (ii) known to be relevant to an attempt to solve any problem with which this specification is concerned.        
Power-driven closures—such as roller doors, shutters, gates and the like—are very widely used for controlling access to buildings and other areas, such as garages, driveways, warehouses, factories, etc. Such closures are typically driven by an electric drive operator unit positioned to one side of the closure. For an overhead roller door or roller shutter, the output drive shaft of the operator unit is arranged to rotate a drum or similar assembly arranged to rotate about an axle, around which the door is wound and unwound, and the operator unit is mounted at or adjacent to one end of the axle.
Such operator units, particularly those for relatively heavy-duty applications such as industrial doors, gates or shutters, commonly include three-phase electric motor units for driving the closure. Such units therefore require the provision of a three phase power source and a suitable controller for controlling the operation of the motor via the three phase supply.
In such applications, prior art controller and power source arrangements have generally proven to be relatively complex and somewhat inconvenient. Installation needs to be completed by qualified electricians. Further, such arrangements generally provide limited ability for restoring operation in the event a fault occurs. In such instances, the services of a qualified electrician are once again usually required, to perform the appropriate diagnostic tests to determine the nature of the fault and restore the controller operation. Such an exercise effectively removes the operator unit from service until the repair is complete, which is costly and inconvenient.
Accordingly, although controller and power supply arrangements for such operator units are known, there is a need for an improved solution.